What self-generated speech is externally misattributed in psychosis? Testing three cognitive models in a...

Area of Science:

• Cognitive Neuroscience
• Psychiatry
• Clinical Psychology

Background:

• External misattribution of internal speech is a proposed mechanism for hallucination formation in psychosis.
• Research suggests misattribution may occur irrespective of content, be linked to negative self-percepts, or involve trauma memories in individuals with trauma history.

Purpose of the Study:

• To investigate the role of external source monitoring bias in first-episode psychosis.
• To examine if external misattribution is specific to negative content, trauma-related content, or generally biased in individuals with hallucinations.
• To test the hypothesis linking childhood trauma to external misattribution of trauma memories.

Main Methods:

• A source monitoring task using positive, neutral, negative, and trauma words was administered.
• Participants included individuals with first-episode psychosis (n=44) and matched non-psychiatric controls (n=26).
• Psychopathology measures were collected to assess symptom severity and trauma history.

Main Results:

• Individuals with hallucinations did not exhibit an external misattribution bias for all words or specifically for negative words.
• No externalizing bias for trauma words was found in individuals with a history of childhood trauma.
• A significant externalizing bias towards positive words was observed in those experiencing hallucinations.

Conclusions:

• External source monitoring bias may not be a core cognitive process in early-stage psychotic illness.
• The proposed link between childhood trauma and external misattribution of trauma memories was not supported by the findings.
• Hallucinations in early psychosis may involve different cognitive mechanisms than previously theorized, with a potential bias towards positive stimuli.